The King and I is a musical, the fifth by the team of composer Richard Rodgers and dramatist Oscar Hammerstein II. It is based on the 1944 novel Anna and the King of Siam by Margaret Landon, which is in turn derived from the memoirs of Anna Leonowens, governess to the children of King Mongkut of Siam in the early 1860s. The musical's plot relates the experiences of Anna, a British schoolteacher hired as part of the King's drive to modernize his country. The relationship between the King and Anna is marked by conflict through much of the piece, as well as by a love that neither can admit. The musical premiered on March 29, 1951, at Broadway's St. James Theatre. It ran nearly three years, then the fourth longest-running Broadway musical in history, and has had many tours and revivals.

It is 1862 in Siam when an English widow, Anna Leonowens, and her young son arrive at the Royal Palace in Bangkok, having been summoned by the King to serve as tutor to his many children and wives. The King is largely considered to be a barbarian by those in the West, and he seeks Anna's assistance in changing his image, if not his ways. With both keeping a firm grip on their respective traditions and values, Anna and the King grow to understand and, eventually, respect one another, in a truly unique love story.

The show was most recently revived on Broadway in 1996, starring Donna Murphy as Anna, who won a Tony Award for her performance, and Lou Diamond Phillips as the King. The production was nominated for eight Tony Awards, winning best revival and three others.